Process for the treatment of edible crustacea



Oct. 18, 1966 J. MARTIN 3,278,983

PROCESS FOR THE TREATMENT OF EDIBLE CRUSTACEA Original Filed April 19 1960 6 Sheets-Sheet 1 INVENTOR JOHN MARTIN Oct. 18, 1966 J. MARTIN PROCESS FOR THE TREATMENT OF EDIBLE CRUSTACEA Original Filed April 19. '1960 6 Sheets-Sheet 2 tn kw mm mm mm 2 Q E m TLFJQ lNl/E/VTOR J'OHN MARTIN PROCESS FOR THE TREATMENT OF EDIBLE CRUSTACEA Original Filed April 19. 1960 J. MARTIN Oct. 18, 1966 6 Sheets-Sheet 5 TNN 7 N lNl/E/VTOR JOH N MARTIN PROCESS FOR THE TREATMENT OF EDIBLE CRUSTACEA Original Filed April 19. 1960 J. MARTIN Och 18, 1966 6 Sheets-Sheet 4 INVENTOR J OH N MART 1 N Oct. 18, 1966 v J. MARTIN 3,278,983

PROCESS FOR THE TREATMENT OF EDIBLE CRUSTACEA Original Filed April '19, 1960 e Sheets-Sheet 5 INVENTOR J OH N MART I N Oct. 18, 1966 T J. MARTIN 3,278,983

.PROUESS FOR THE TREATMENT OF EDIBLE CRUSTACEA Original Filed April 19. 1960 e Sheets-Sheet e m Elwin] I Q N a a? INVENTOR JOHN MARTIN 926, issued November 19, 1963. moving the edible flesh in one piece from the severed tail United States Patent Original application Apr. 19, 1960, Ser. No. 23,177, now

Patent No. 3,220,049, dated Nov. 30, 1965. Divided and this application June 1, 1965, Ser. No. 465,236 11 Claims. (Cl. 17--45) This application is a division of my application No. 23,177, now US. Patent 3,220,049, of Nov. 30, 1965.

This invention relates to an improved process for the treatment of crustacea such as crayfish, prawns and the like, and particularly the species known as Dublin Bay prawns (Nephrops norvegz'ous), to remove the edible flesh from the tail portions and render it ready for marketing as processed products for human consumption. The tail portions of these creatures are severed from the non-edible head and body portions, and they then require to have the edible flesh separated from the enclosing shell.

It is Well known that according to the methods 'of processing hitherto practised considerable skill is required for, not only must the shell be removed from the fleshy edible part, but also it is necessary to remove the contents of the black vein or sand sac which runs substantially the full length of the tail of the prawn, and terminates at the tail end of the fish in the central tail fin. Hitherto this last requirement has been met by removing the vein itself, with its contents, if necessary with the use of tweezers or like tools. The apparatus for automatically removing,

or flushing out, this black vein is described and illustrated herein, but is the subject matter of my Patent No. 3,110,- The apparatus for reportions of crustacea is set forth in my Patent No. 3,220,-

049, issued Nov. 30, 1965.

' crustacea to separate the edible flesh of the tail was effected entirely by manual operation, and consequently was slow and laborious even with skilled labor and therefore the ultimate product (known in the trade as scampi) was relatively costly. Further, only comparately unskilled labor was available, and the flesh portion was often broken and/or a high proportion of the flesh was left adhering to the shell during the removal process, and thrown to Waste, both which detects reduced the yield of best quality scampi and added to the cost of the ultimate product.

The object of the invention is to provide an improved process for the treatment of these edible crustacea whereby the removal of the shell from the edible flesh of the tail portion can be effected easily and quickly, and with comparatively unskilled labor, so that a much better and cheaper product results.

The present invention provides a method of processing the tail portions of crustacea such as crayfish, prawns and the like to separate the edible flesh wherein the crustacea 'tail is held by means which engages the surrounding shell and, while so held, has the enclosed flesh portion removed therefrom by fluid pressure introduced into the shell at its smaller end. This removal of the flesh from the shell will be accomplished by the use of either air or water ejected under suitable pressure from a nozzle in serted into the shell of the tail at or near the anus.

Another object of the invention is to provide a method and means for feeding crustacea tails first to a water nozzle applied to the anus for the flushing out of the sand sac,

,1 3,278,983 Patented Oct. '18, 1966 "ice and then to an air nozzle inserted into the tail for ejection of the flesh from the shell.

In this connection the arrangement may be characterized by a first plurality of tail holders arranged side by side, each with a flushing water nozzle, followed by a second plurality of tail holders each with a flesh removing air nozzle, all at equal spacing so that an intermittent conveyor may feed a series of untreated crustacea tails to the first plurality of nozzles while simultaneously moving a like series of flushed crustacea tails on to the flesh removing nozzles. Thereby, one series of the fish tails may have the sand sac flushed out, with water, while another series, already flushed has the edible flesh portion removed from the shell, by air.

Other objects and advantages of the invention will be apparent from the claims, the description of the drawing and from the drawing in which:

FIG. 1 is a perspective view partly in sectionof the tail portion of a crayfish, from the larger, severed end;

FIG. 2 is an elevation of a machine which will automatically feed the crustacea tails one after another to a holding means, insert an air nozzle into the rear end of the held tail and, after ejection of the edible flesh from the shell, will convey away both the ejected flesh and the empty shell to respective collectors;

FIG. 3 is a plan of the machine shown in FIG. 2;

FIGS. 4 and 5 are side elevation and plan respectively of one form of means for holding the crustacea tail while the sand sac is flushed out or the fleshy body is removed from the shell;

FIGS. 6 and 7 are a sectional side view and a fragmentary rear view of the means for holding, flushing and releasing the crustacea tail at the flushing station shown in FIG. 3; I

FIGS. 8 and 9 are respectively side elevation and front view of a part of a driving means for giving alternating intermittent movements to parts of the mechanism shown .in FIGS. 2 and 3;

FIG. 10 is a diagram showing the layout of the pneumatic system the main pomponents of the machine, and FIG. 11 is a perspective view of one of the air nozzles for insertion into the shell of the tail.

Referring first to FIG. 1 the tail portion of a crayfish, the severed head and body part of which has been discarded as waste, has an upper regulated hard shell. a the lower extremities of which have a notched form providing recesses b between feet or fins c. This shell a is bridged by a flexible horny membrane d forming the underskin between which and the said shell a the edible flesh e is held. This flesh is traversed by the sand sac or vein terminating at the anus g in the centre tail f-in h, between two horn-like protuberances i. There are also two side tail fins j.

Referring now in the main to FIGS. 2 to 5 and 8 to 10, a machine for mechanically and automatically carrying out a continuous process according to the invention comprises a base 10 (which .would be the top of a table-like structure) on which is mounted an electric motor 11 (this could be below the base 10), the motor driving by a belt and pulley drive 12, a cam shaft 13. At one end this cam shaft 13 drives a double Geneva .motion 14 (see FIGS. 8 and 9), one part of which gives an intermittent drive to the shaft 15 of an endless belt discharge conveyor 16 arranged to convey away the ejected flesh portions of the crustacea tails after they have been ejected from their shells by an air nozzle as is explained below. The shaft 15 also drives a transit conveyor 24 described below.

The other part of the Geneva motion gives an intermittent drive to bevel gears 17, 18, the latter being fixed to a shaft 19, which, through a chain 20 and sprockets 21 imparts the intermittent drive to an endless belt feed conveyor 22. Obviously,-because of the Geneva 'The crustacea tails, 'in some cases after removal of one or more of the tail tins, are delivered singly and in-end to end order, rear end foremost, to the feed conveyor belt 22 by hand or by any suitable automatic means. There could be for example, a means receiving them in random arrangement and so orientating them that they are delivered to the belt 22 in end-to-end spaced relationship with the rear end leading. It is necessary, in the machine shown, that the tails reach the transit conveyor 24 upside down as well as the rear end leading.

Each tail of a prawn or the like arriving at the delivery end of feed conveyor 22 is delivered therefrom to one of a number of shallow troughs, buckets or scoops 23, arranged transversely of and spaced along the length of the said transit conveyor v24 which is disposed at right angles to the feed conveyor 22 (see especially FIG. 3) and such transit conveyor is driven intermittently by the shaft 15 in step with and at the same speed as the conveyors 16 and 22 but, as explained above, conveyor 22 is a step in advance of conveyor 24 so that it always delivers to a stationary trough or bucket 23 on the conveyor 24.

To assist in the complete transfer into the trough 23 an air nozzle 22 is arranged to discharge periodic jets of air' as the correct time to blow the tail into the stationary trough. The mechanisms for this is explained below. A stop plate .24 along the front of conveyor 24 serves as a limit stop when engaged by the tail fins h and j.

The transit conveyor 24 is adapted by its stepwise movements to locate each prawn or like tail in turn below a holding means and, when so disposed and held, each tail remains stationary (the conveyor being stationary at such time) ready to receive a slidably mounted ejector air nozzle 33 as the latter is moved towards the adjacent end of the prawn on actuation of the pneumatic system diagrammatically illustrated in FIG. 10. This nozzle is of spear head form (see FIG. 11) so as to pierce the horny membrane d in the region of the anus g as it is jabbed into the tail.

One form of holding means is shown in FIGS. 4 and 5.

'It comprises a pneumatic cylinder 25 ,with a vertically slidable ram 26, and to the lower end of said ram is attached a crosshead 27, guided by sliding rods 27 and carrying on its under face a resilient presser block or pad 27 As illustrated more clearly in FIG. 4, the pad or block 27 is inclined on its under surface so as to accommodate itself to the tapering form of the crustacea tail. As these tails vary in size, the troughs 23 of the transit conveyor 24 may be of a springy material,

e.g. a fle'xible but stiff synthetic material so as in the case of small tails, to be deformed by the descending pad 27' until that pad engages the tail with a holding pressure.

In the form illustrated the conveyor 24 is made up of two roller chains to which the buckets or scoops 23 are attached. In order to resist the downward thrust of the pad 27, supports 1 standing up from the base engage the ends of the bucket 23 when under the pad and spread them'on a supporting bracket (see the part 1 in FIG. 4 or the part 29 in FIG. 6) just before the ejector air nozzle 33 (described below) moves for- Ward to penetrate the tail. The nozzle 33 moves in a direction parallel to the longitudinal axis of the severed tail portion, toward the severed, larger end of the tail portion. ('FIG. 2 and FIG. 4.)

As stated above, the machine illustrated requires that the tails be upsidedown. In order to prevent their turning over under the stepwise jerky advance of the conveyor, and in order also to resist the tendency of the longitudinally advancing nozzle 33 to push the tails along the scoops or buckets, wire guides 24 and 24 are provided, mounted at their ends on suitable fixed parts of the machine and adapted to engage in some of the recesses b of the tails. Furthermore, the wire 24 is deflected in the approach to the holding means so as to assist in flattening out the tail fins. This is important not only to ensure that the advancing nozzle 33 will be above the centre tail fin h but also to ensure that the horn-like protuberances i are in position to engage the sides of the nozzle and center the tail relativelyv to the axis of the nozzle.

Located in the bracket 28 is a second cylinder 30, disposed horizontally, that is at right-angles to the air cylin- 'der 25. This cylinder 30 has a ram 31 on which is mounted the nozzle housing 32 from which extends the said air nozzle 33. The nozzle 33 is removable for interchange or cleaning or sharpening. It is of spear head form, see FIG. 11, with sharpened side edges and a point adapted to pierce the horn-like membrane d of the tail. The air outlets of the nozzle are in its underside.

Opposite the nozzle 33 and running along the rear edge of the discharge conveyor 16 is a stop plate 16- which obstructs the flesh ejected from the shells by the nozzle and causes it to remain on or to drop back on to the discharge conveyor.

As will be clear from FIGS. 3 and 10 the pneumatic system also includes a further nozzle 34 adapted to remove the empty shells from the conveyor 24 afterthey have been operated on by the ejector air nozzle 33, and to pass them into a chute 34 supply is delivered to each of the several nozzles as and when required, in timed relationship with the various mechanical operations of the machine.

10 below the cam shaft 13, in which block are four air valves 36, 37, 38 and 39 adapted to be operated respectively by earns 40, 41, 42 and 43 fixed on the cam shaft 13. By this arrangement the four valves are actuated.

wise succession by the feed conveyor 22 and are delivered one by one to the successive scoops or buckets 23 of the conveyor 24 in upside down position at a loading 1 station 56 with their tail fins extending towards the'front of the machine; The conveyor 24 is moved stepwise: and each prawn or the like in turn becomes positioned I beneath the holding means,'first at the flushing station 1 Also shown in FIGS. 3 and 10 is the control means whereby the pressure airj Such control. means comprises a valve block 35 located on the base 51 and then at the de-shelling station 53. Atthe deshelling station 53 air is admitted to the cylinder 25by air valve 37 and the presser block or pad 27 moves downwards to hold the prawn or liketail againstthe: stationary bucket or scoop 23 to hold the tail and await. 1

the insertion into the tail of the ejector air nozzle 33' 'which is elfected by actuation of the air valve 38 toadrnit air to cylinder 30 to. move; the nozzle and its housing towards'the prawn. I

Actuation of air valve 37 also admits air to the tail fin nozzle 29 which releases an air blast to spread the tail fin to ensure that as and when the nozzle 33 moves on to the tail the latter is correctly disposed and insertion is effected at the correct point. The blast or air from nozzle 33, under control of valve 39 then ejects the fleshy body portion of the tail from the shell on to the discharge conveyor 16. The presser pad 27 is now lifted to release the prawn, and the conveyor belts are all moved by their respective Geneva motions to bring the next prawn or the like beneath the holding means, and to move both the ejected flesh on conveyor 16, and the empty shell in the scoop 23 towards their respective collecting points.

It will be seen from FIG. that the ejector air nozzle 33 which removes the edible fleshy body from the shell, and the nozzle 34 at discharge station 57 for removal of the empty shell out of the conveyor 24 are on the same air line and therefore operate simultaneously, so that as nozzle 33 is effecting removal of the flesh from one tail, the other nozzle 34 is blowing the empty shell of another tail from the conveyor 24. The tail jet 29 and the presser pad 27 may also be actuated simultaneously. The strength of the air blast from the nozzle 34 is enough to remove an empty tail shell from conveyor 24, but is not suflicient to remove a prawn or like tail which has not been successfully operated upon by the ejector nozzle 33. By this arrangement, the empty shells and the full shells or only partly-emptied shells are delivered separately from the machine into their respective receptacles.

Each body successfully and cleanly ejected from its shell eventually falls off the end of the conveyor 24 into a chute 24 leading to a collecting receptacle (not shown).

The pneumatic system includes a reducing valve 54, a gauge 55, and a flow regulator, in order to ensure good control of the air pressure and successful operation of the machine. The air pressure supply may be from a separate compressor unit and accumulator, or such unit may be built into the machine.

Referring now to FIGS. 6 and 7, the flushing operation for cleaning out the contents of the sand sac or vein (with or without the vein itself) may either precede or occur simultaneously with the separation of the edible flesh from the shell. In this case flushing of the sand sac takes place at one station, such as station 51, and separation of the edible flesh from the shell takes place at another point, such as station 53.

As shown, there is an upright stand 61 with overhanging arm 62, this stand being built on the base or table 10 of the machine. Said arm 62 carries a pneumatic cylinder 63 whereby a head 44 may be raised and lowered, being guided by the rods 45. This head 44 is fitted on its lower side with a resilient pad 46 adapted, as the head descends, to grip the tail with a gripping pressure along the whole length of the tail, the tail at the time being held in the bucket or scoop 23.

Carried by the head 44 is a plate 47 from which is suspended a block 48, there being compression springs 49 between this block and the plate 47. The block 48 is ported at 50 and receives water under the control of a fifth valve (not shown) operated from the before-mentioned cam shaft '13.

Below the said block 48 is .a rubber or like resilient nozzle 52, the orifice of which is in communication with the said port 50, and the lower end of which is tapered so as to be co-planar with the lower face of the pad 46 when the parts are unstressed. Such orifice is large enough to ensure its being open to the anus of the tail, regardless of the size of the tail. The resilient nozzle 52, forms a flexible seal therearound for directing fluid under pressure into the anus without piercing the skin, penetrating the anus or requiring exact registration.

In operation, with a tail lying in the scoop 23 and held stationary below head 44, first the tail is gripped by the descending pad 46 and then water under pressure is admitted to the port *50. Because, at that time the outlet of the nozzle '52 is in register with the adjacent end of the sand sac in the tail, the water jet or stream from the nozzle flushes the contents of the sac out at the larger end of the tail. Thereafter, the water is shut oif by .the valve 39, or by the said fifth valve, the head 44 is raised and the bucket 23 is moved on by the conveyor 22 to the next station, indicated at 53 in FIG. 7, where the body of the creature is ejected from the shell as set forth above.

As explained above, flushing of the sand sac takes place at one station and separation of the edible flesh'fro'm the shell takes place at another point, the flushing head being followed immediately by the deshelling station. The stepwise movement of the conveyor 24 is such as to take each scoop 23 through a station at each step, thereby bringing one unprocessed tail portion to the flushing head and one flushed tail portion to the deshelling station at each step of movement.

I claim:

1. The method of processing the tail portions of crustacea such as crayfish, prawns and the like, from which the heads have been previously removed, which comprises the steps of holding the said crustacea tail portion by engagement with the outer shell thereof, then flushing out the sand sac, or vein, in said tail portion with liquid under pressure applied to the region of the arms at the small end thereof and then expelling the edible flesh in one piece from said shell by a fluid force introduced into the shell at its smaller end.

2. A continuous method for processing the tail portions of crus-tacea, such as crayfish, prawns and the like, from which the heads have been previously removed, which comprises the steps of intermittently conveying a plurality of sail tail portions individually and successively along a path to a flushing station and then to a de-shelling station with halts at said stations; holding the shell of each successive tail portion, halted at said flushing station, against movement and while so held applying liquid under pressure to the region of, and directing said liquid into and flushing out the sand sac or vein, and then holding the shell of each said tail portion, halted at said de-shelling station, against movement and While so held introducing a fluid force into the small end of the shell and expelling the edible flesh from the large end thereof in one piece.

3. A method as specified in claim 2 wherein said holding steps include the steps of unyieldably supporting the central portion of the hard upper shell of each tail portion, yieldably and resiliently supporting the opposite side portions of said hard upper shell and yieldably and resiliently pressing the entire soft lower membrane of each tail portion toward the said central portion of the upper hard shell thereof whereby the exterior of said tail portion is yieldably clamped against an unyieldable support.

4. A method as specified in claim 2 wherein said holding step includes the steps of mechanically pressing the horny membrane of each said tail portion toward an unyieldable support while pneumatically pressing the tail fins of each said tail portion toward an unyieldable support and pneumatically spreading said tail fins.

5. A method as specified in claim 2 wherein said step of introducing a fluid force into the small end of said shell at said de-shell-ing station includes the steps of piercing an air nozzle through the horny membrane forming the underskin at the small end of each said .tail portion and then blasting air under pressure from said nozzle into the said small end of said tail portion.

6. A continuous method for removing the edible flesh, in one piece, from the shell of tail portions of crust-acea, such as crayfish, prawns and the like, from which the head portions have been previously severed which comprises the steps of advancing a plurality of said tail portions along a path; halting said tail portions individually and successively at a .de-shelling station on said path; holding the outer shell of each said tail portion, halted at said station against movement; piercing an opening into the interior of the small end of each said tail portion so held at said station; introducing fluid under pressure through said opening and exerting the force of said fluid on the edible flesh within the small end of said tail portion while so held until said flesh is expelled in one piece from the large end of said tail portion and then continuing the advance of the shells of said tail portions along said path and away from said de-shelling station.

7. The method of using a nozzle for removing the edible flesh, in one piece, from the shell of tail portions of crustacea, such as crayfish, prawns, and the like, from which the head portions have been previously severed, said method comprising the .steps of holding the said tail portions against movement in -a direction parallel to the longitudinal axis thereof by engagement with the outer shell of said tail portion, and, while so held, advancing said nozzle substantially in parallelism with said axis through said shell into the interior of the small end of said tail portion, then introducing fluid under pressure from said nozzle into said shell interior, and exerting the force of said fluid on the edible flesh within said small end of said tail portion until said edibile flesh is expelled in one piece from the said larger, severed end of said tail portion.

8. A method as specified in claim 7, wherein said step of advancing said nozzle into the interior of said shell is accomplished :by piercing said nozzle through the horny membrane, forming the underskin at the small end of said tail portion, while guiding the side edges of said nozzle on the horn-like protuberances of the tail portion, to thereby centre said tail portion relative to the axisof said nozzle.

9. A method as specified in claim 7, wherein said holding step includes the step of applying a blast of fluid downwardly onto the tail fins of said tail portion, prior to the step of advancing said nozzle into said shell to thereby flatten said tai-l fins.

10. A method as specified in claim 7, plusthe step of mechanically flattening out the centre-tail fin of said tail portion, prior to the step of advancing said nozzle into said shell to ensure that said nozzle will be above said centre fin during said advance into said shell.

11. The method of nozzle ejecting the edible flesh in one piece from the elongated shell of tail portions of crustacea, such as crayfish, prawns, and the like, from which the head portions have been previously severed, said method comprising the steps of supporting said tail portion and nozzle in substantially coplanar, coaxial relationship, with the small end of said tail portion facing the pointed portion of said nozzle; then relatively advancing one said portion toward the other coaxially and cansing the pointed portion of said nozzle to pierce, through the shell of said tail portion into the interior of said shell and then exerting fluid presure from said nozzle within said shell against the edible flesh t'hereWithin in the direction of the severed larger end thereof until said flesh is ejected in one piece therefrom.

References Cited by the Examiner UNITED STATES PATENTS 2,838,786 6/ 1958 Ward 17-2 FOREIGN PATENTS 145,140 2/ 1952 Australia. 150,306 2/ 3 Australia.

SAMUEL KORE/N, Primary Examiner.

LUCIE H. LAUDENSLAGER, Examiner. 

1. THE METHOD OF PROCESSING THE TAIL PORTION OF CRUSTACEA SUCH AS CRAYFISH, PRAWNS AND THE LIKE, FROM WHICH THE HEADS HAVE BEEN PREVIOUSLY REMOVED, WHICH COMPRISES THE STEPS OF HOLDING THE SAID CRUSTACEA TAIL PORTION BY ENGAGEMENT WITH THE OUTER SHELL THEREOF, THEN FLUSHING OUT THE SAND SAC, OR VEIN, IN SAID TAIL PORTION WITH LIQUID UNDER PRESSURE APPLIED TO THE REGION OF THE ANUS AT THE SMALL END THEREOF AND THEN EXPELLING THE EDIBLE FLESH IN ONE PIECE FROM SAID SHELL BY A FLUID FORCE INTRODUCED INTO THE SHELL AT ITS SMALLER END. 